18 research outputs found

    Synergistically Constructed Electromagnetic Network of Magnetic Particle-Decorated Carbon Nanotubes and MXene for Efficient Electromagnetic Shielding

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    Lightweight polymer-based nanostructured aerogels are crucial for electromagnetic interference (EMI) shielding to protect electronic devices and humans from electromagnetic radiation. The construction of three-dimensional (3D) conductive networks is crucial to realize the excellent electromagnetic shielding performance of polymer-based aerogels. However, it is difficult to realize the interconnection of different conductive fillers in the polymer matrix, which limits the further improvement of their performance. Herein, 3D ordered hierarchical porous Fe3O4-decorated carbon nanotube (Fe3O4@CNT)/MXene/cross-linked aramid nanofiber (c-ANF)/polyimide (PI) aerogels were prepared via a unidirectional freezing strategy. Benefiting from the magnetic loss effect of Fe3O4 magnetic nanoparticles, the conductive and dielectric loss effects of CNTs, and the multiple reflections induced by the 3D ordered hierarchical porous structure, the Fe3O4@CNTs/MXene/c-ANFs/PI (FMCP) aerogels with the same contents of 8 wt % of Fe3O4@CNTs and MXene exhibit a high absolute EMI shielding effectiveness (SE) of up to 67.42 dB and a microwave reflection (SER) of 0.60 dB. More importantly, the phase transition of a small amount of MXene to TiO2 optimizes the impedance matching and transmission and then improves the microwave absorption. The FMCP aerogel has an outstanding normalized surface specific SE (SSE/t) which is up to 62,654 dB cm2·g–1. Meantime, the FMCP aerogels also show super-elasticity and could maintain 91.72% of the maximum stress after 1000 cycles of compression release under a fixed deformation of 60%

    Optimizing nitrogen fertilizer and straw management promote root extension and nitrogen uptake to improve grain yield and nitrogen use efficiency of winter wheat (<i>Triticum aestivum L.</i>)

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    Straw returning is an efficient straw usage strategy in rice-wheat rotation, but nitrogen (N) use efficiency (NUE) was decreased due to incorrect straw and N fertilizer managements. To investigate the effects of straw and N fertilizer management on root growth, N fertilizer fates, grain yield and NUE of wheat, a two-year field and micro-plot 15N-labelled experiment under three levels of N application rate (0, 180 and 240 kg N ha−1) with two basal N application stages [seeding (BN), and 3-leaf stage (TN)] and three straw treatments [no straw return (NS), straw return by rotary tillage (SR) and straw return by ploughing (SP)] was conducted. The results indicated that SP increased grain yield and NUE, and the increase was highest under TN180. SP increased N uptake by enhancing root extension and soil N supply capacity, and TN decreased 15N residual in 60–100 cm soil layer. SP and TN180 both decreased 15N fertilizer loss and increased 15N recovery. Reducing basal N and applied at third-leaf stage (TN180) under SP had the same grain yield level as conventional N management (BN240) under NS, while highly improved NUE due to more root extension in deep soil layer and less N fertilizer loss.</p

    Data_Sheet_1_Development and evaluation clinical-radiomics analysis based on T1-weighted imaging for diagnosing neonatal acute bilirubin encephalopathy.docx

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    PurposeTo investigate the value of clinical-radiomics analysis based on T1-weighted imaging (T1WI) for predicting acute bilirubin encephalopathy (ABE) in neonates.MethodsIn this retrospective study, sixty-one neonates with clinically confirmed ABE and 50 healthy control neonates were recruited between October 2014 and March 2019. Two radiologists' visual diagnoses for all subjects were independently based on T1WI. Eleven clinical and 216 radiomics features were obtained and analyzed. Seventy percent of samples were randomly selected as the training group and were used to establish a clinical-radiomics model to predict ABE; the remaining samples were used to validate the performance of the models. The discrimination performance was assessed by receiver operating characteristic (ROC) curve analysis.ResultsSeventy-eight neonates were selected for training (median age, 9 days; interquartile range, 7–20 days; 49 males) and 33 neonates for validation (median age, 10 days; interquartile range, 6–13 days; 24 males). Two clinical features and ten radiomics features were finally selected to construct the clinical-radiomics model. In the training group, the area under the ROC curve (AUC) was 0.90 (sensitivity: 0.814; specificity: 0.914); in the validation group, the AUC was 0.93 (sensitivity: 0.944; specificity: 0.800). The AUCs of two radiologists' and the radiologists' final visual diagnosis results based on T1WI were 0.57, 0.63, and 0.66, respectively. The discriminative performance of the clinical-radiomics model in the training and validation groups was increased compared to the radiologists' visual diagnosis (P ConclusionsA combined clinical-radiomics model based on T1WI has the potential to predict ABE. The application of the nomogram could potentially provide a visualized and precise clinical support tool.</p

    Data_Sheet_2_Development and evaluation clinical-radiomics analysis based on T1-weighted imaging for diagnosing neonatal acute bilirubin encephalopathy.CSV

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    PurposeTo investigate the value of clinical-radiomics analysis based on T1-weighted imaging (T1WI) for predicting acute bilirubin encephalopathy (ABE) in neonates.MethodsIn this retrospective study, sixty-one neonates with clinically confirmed ABE and 50 healthy control neonates were recruited between October 2014 and March 2019. Two radiologists' visual diagnoses for all subjects were independently based on T1WI. Eleven clinical and 216 radiomics features were obtained and analyzed. Seventy percent of samples were randomly selected as the training group and were used to establish a clinical-radiomics model to predict ABE; the remaining samples were used to validate the performance of the models. The discrimination performance was assessed by receiver operating characteristic (ROC) curve analysis.ResultsSeventy-eight neonates were selected for training (median age, 9 days; interquartile range, 7–20 days; 49 males) and 33 neonates for validation (median age, 10 days; interquartile range, 6–13 days; 24 males). Two clinical features and ten radiomics features were finally selected to construct the clinical-radiomics model. In the training group, the area under the ROC curve (AUC) was 0.90 (sensitivity: 0.814; specificity: 0.914); in the validation group, the AUC was 0.93 (sensitivity: 0.944; specificity: 0.800). The AUCs of two radiologists' and the radiologists' final visual diagnosis results based on T1WI were 0.57, 0.63, and 0.66, respectively. The discriminative performance of the clinical-radiomics model in the training and validation groups was increased compared to the radiologists' visual diagnosis (P ConclusionsA combined clinical-radiomics model based on T1WI has the potential to predict ABE. The application of the nomogram could potentially provide a visualized and precise clinical support tool.</p

    High-Thermal-Transport-Channel Construction within Flexible Composites via the Welding of Boron Nitride Nanosheets

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    Efficient heat dissipation is a prerequisite for further improving the integration of devices. However, the polymer composites are not satisfying heat dissipation. For that reason, high-thermal-transport channels were manufactured by the direct freezing method and boron nitride nanosheets (BNNS) were further welded by carbonization. Composites with high thermal conductivity (7.46 W m–1 K–1) were obtained by immersion in poly­(dimethylsiloxane) (PDMS). Thermal conductivity enhancement of composites reached about 3900% at 15.8 vol % loading of BNNS. Besides, the composites maintained the structural flexibility of PDMS and allowed repeated bending and twisting. In addition, the PDMS composites exhibited excellent antistatic properties because of a conductive network formed by residual carbon. Therefore, dust could be avoided and the surface kept clean. This provides a better choice for thermal management materials and meets the antistatic requirements of the devices

    Electrochemical enantiomer recognition based on sp3-to-sp2 converted regenerative graphene/diamond electrode

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    It is of great significance to distinguish enantiomers due to their different, even completely opposite biological, physiological and pharmacological activities compared to those with different stereochemistry. A sp(3)-to-sp(2) converted highly stable and regenerative graphene/diamond electrode (G/D) was proposed as an enantiomer recognition platform after a simple beta-cyclodextrin (beta-CD) drop casting process. The proposed enantiomer recognition sensor has been successfully used for D and L-phenylalanine recognition. In addition, the G/D electrode can be simply regenerated by half-minute sonication due to the strong interfacial bonding between graphene and diamond. Therefore, the proposed G/D electrode showed significant potential as a reusable sensing platform for enantiomer recognition

    Efficient Thermal Transport Highway Construction Within Epoxy Matrix via Hybrid Carbon Fibers and Alumina Particles

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    Polymer composites with excellent thermal conductivity and superior mechanical strength are in high demand in the electrical engineering systems. However, achieving superior thermal conductivity and mechanical properties simultaneously at high loading of fillers will still be a challenging issue. In this work, a facile method was proposed to prepare the epoxy composite with carbon fibers (CFs) and alumina (Al2O3). This CF and Al2O3 hybrid structure can effectively reduce the interfacial thermal resistance between the matrix and the CFs. The thermal conductivity of epoxy composite with 6.4 wt % CFs and 74 wt % Al2O3 hybrid filler reaches 3.84 W/(m K), which is increasing by 2096% compared with that of pure epoxy. Meanwhile, the epoxy composite still retains outstanding thermal stability and mechanical performance at high filler loading. A cost-effective avenue to prepare highly thermally conductive and superior mechanical properties of polymer-based composites may enable some prospective application in advanced thermal management

    High-Thermal-Transport-Channel Construction within Flexible Composites via the Welding of Boron Nitride Nanosheets

    No full text
    Efficient heat dissipation is a prerequisite for further improving the integration of devices. However, the polymer composites are not satisfying heat dissipation. For that reason, high-thermal-transport channels were manufactured by the direct freezing method and boron nitride nanosheets (BNNS) were further welded by carbonization. Composites with high thermal conductivity (7.46 W m–1 K–1) were obtained by immersion in poly­(dimethylsiloxane) (PDMS). Thermal conductivity enhancement of composites reached about 3900% at 15.8 vol % loading of BNNS. Besides, the composites maintained the structural flexibility of PDMS and allowed repeated bending and twisting. In addition, the PDMS composites exhibited excellent antistatic properties because of a conductive network formed by residual carbon. Therefore, dust could be avoided and the surface kept clean. This provides a better choice for thermal management materials and meets the antistatic requirements of the devices

    Enhanced Thermal Conductivity of Nanodiamond Nanosheets/Polymer Nanofiber Composite Films by Uniaxial and Coaxial Electrospinning: Implications for Thermal Management of Nanodevices

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    Nanotechnology is gradually applied to the preparation of heat dissipation materials with the miniaturization of electronic devices. Electrospinning technology has received extensive attention due to its unique advantages in constructing continuous nanofibers. In this work, uniaxial-polyvinyl alcohol/nanodiamond (U-PVA/ND) and coaxial-polyvinyl alcohol/nanodiamond (C-PVA/ND) composite fiber films with different microscopic morphologies were constructed by uniaxial and coaxial electrospinning. The results show that the thermal conductivities of U-PVA/ND and C-PVA/ND composite fibers with 60 wt % ND content are 71.3 and 85.3 W m–1 K–1, respectively, which are 171.2 and 205.1 times greater than that of the pure PVA fiber film. In addition, the maximum thermal decomposition temperature (Tmax) and volume resistivity of the C-PVA/ND composite fiber film were 364.3 °C and 2.29 × 1015 Ω·cm, respectively, demonstrating the excellent thermal stability and electrical insulation of the composite fiber film. This experiment results provide strong evidences of electrospinning technology for the preparation of highly thermally conductive composites. So, thermally conductive films can be used as the outer layer of electronic components to accelerate their heat dissipation and extend their service life
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